Numerous substances have been proposed and/or used as non-nutritive sweeteners; these substances do not have a caloric effect, but still impart a sweet taste. Such substances enable individuals who must limit their intake of the natural sugars to control various health conditions, including diabetes and obesity. Many of these substances or sweeteners have severe disadvantages, such as a bitter aftertaste or toxic side effects, at the same concentrations necessary to obtain the sweetening effect. Only two types of non-nutritive sweeteners are used to any extent: saccharin-type and cyclamate-type.
Other sweeteners are described in U.S. Pat. Nos. 3,087,821; 3,294,551; 3,515,727; 3,597,234; and 3,899,592. U.S. Pat. No. 3,087,821 describes the use of dihydrochalcone compounds as sweeteners. In U.S. Pat. No. 3,294,551, Herbst discloses the use of 5-carbocyclicaminotetrazole compounds and their salts as sweeteners. U.S. Pat. Nos. 3,515,727 and 3,597,234 describe monohydroxyphenoxytetrazole compounds and their salts as sweeteners. U.S. Pat. No. 3,899,592 shows that the dextro enantiomorph of certain 6-substituted tryptophane compounds can be used as sweeteners.
Since it is well known that even small changes in chemical structure will often destroy sweetening activity, the already known sweeteners do not enable one skilled in the art to predict the chemical structures of other sweeteners.